Field of Invention
The present invention relates to a transistor and a method of manufacturing the same, and more particularly to a trench gate MOSFET and a method of manufacturing the same.
Description of Related Art
Power switch transistors are widely used in power switch elements such as power supplies, rectifiers, low voltage motor controllers or the like. In a conventional power switch transistor structure, a trench gate electrode includes a top electrode, a bottom electrode, and a thick oxide layer between the bottom electrode and the substrate. The potential lines at the bottom of the trench are dense, so a thick bottom oxide layer is required to prevent breakdown. Besides, in order to evenly distribute the potential lines at both sides of the trench, the oxide layer on the trench sidewall is required to have a certain thickness corresponding to an operating voltage for the device. The minimum thickness of this thick oxide layer has its limit to ensure the device performance, and thus, the minimum width of the trench is accordingly limited.